Necticut



G. E. WHITNEY.

PRESS.

APPLICATION FILED 050.14. IIIIs.

atentcISopt. 23, 1919.

In Q

IIIIIII ||L Tm: coLuMuIA PLANocIIMI'II cn., WASHINGTON. U- C.

G. E. WHITNEY.

PRESS.

APPLICATION man nEc.14.|91e.

Patented Sept. 23, 1919.

m QQ

G. E. WHITNEY.

PRESS.

APPLICATION FILED DEC. I4. 191s.

Patented Sept. 23, 1919.

4 SHEETS-SHEET 3.

G. E. WHITNEY.

PRESS.

APPLlcAloN man 0Ec.|4. |916.

1 ,3 1 '7, 1 1 7 Patented Sept. 23, 1919.

'rmx summum 'LANonuM-l 60,. wAslllNGToN. lx C.

GEORGE E. WHITNEY, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR T0 INTERNATIONAL PAVEMENT COMPANY, OF HARTFORD, CONNECTICUT, A CORPORATION NECTICUT.

or" QON- Speciication of Letters Patent.

:PatentedY sept. 2e, 1919.

Application med December 14, 1916. Serial No. 137,033".

T0 all 'whom it may concern:

Be it known that I, GEORGE E. WHITNEY, a citizen of the United States, and a resident of Bridgeport, in the county of Fairfield and State of Connecticut, have invented an Improvement in Presses, of which the following` description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention pertains to improvements in presses and more particularly, though not exclusively, to improvements in presses, adapted for applying great pressure to plastics confinedr in a mold, which is automatically filled', covered and emptied by automatic mechanism, coperating with the compressive instrumentalities.

Among the objects of my invention are to provide a molding press capable of applying high pressure at high speed without the frequent interruptions caused by wear, breakage, and the like, which usually attend the operation of this type of press.

Referring to the drawings, which show a preferred construction of one illustrative embodiment of my invention,-

Figure 1 is a side elevation partly in section, showing a preferred embodiment of my invention;

Fig. 2 is a plan view thereof;

Fig. 3 is an end elevation taken from the right of Fig. 1;

Figs. 4l and 5 show the details of the cam mechanism of the press.

rThe press shown vin the drawings is peculiarly well adapted for use in the manufacture of asphalt blocks for paving purposes, whichblocks preferably receive a pressure of about 200 tons on a relatively small surface, such as a inch surface of the usual asphalt paving block.

The .material prior to compression is granular iny form, being composed of a thoroughly mixed aggregate, comprising heated crushed stone, pulverized stone and a bituminous binding agent. This mixture is fed to the press in granular form at about 290O IV., and the compression obtained by the 200 tous of pressure is about'BB-,lper cent., itl inches of uncompressed material being comp-ressible to form a block three inches in thickness.

The irastrumen-talities which coperate to form a press of this type comprise pressure applying instrumentalities and material handling instrumentalities for feeding' material to and from thexmoldf, in which the pressure is applied by the pressure applying instrumentalities.`

In the embodiment of my invention, shownl in the drawings, I referably provide compressing instrumenta ities including a mold plunger 10, adapted to rectilinearl'y reciprocate in a mold 11 and to receive pres"- sure from toggle elements 12 and 13. The straightening of the toggle' to produce c'omprcssive movement of the mold plunger 10 may be actuated in any suitable way, but I prefer to supply a lever arm 14.1, which may be and preferably is unitary with, or rigidly attached to, the' lower toggle element 13, which lever arm 14S is preferably rocked by pressure fluid means typified in the present embodiment of my invention' by the steam cylinder 15.

The steam cylinder 15 may be carried by au extension 16 from the bed plate 17 of the press. Vit'hin the steam cylinder 15, I preferably provide' a reciprocable piston I8 having two piston rods 19, extending through the stuiling boxes 20 inthe cylinder head 21. Connected to the outer ends of the pistons 19, I may and preferably dol provide a cross head 22, which may be and preferably is' connected to the lever element 14, at each end by connecting rods 23. Thus rectilinear to and' fro movement of the piston 1S in the cylinder 15 imparts rocking movement to the lever element 14, which alternately straightens and' bends the toggle formed by the toggle elements 12 and 13', thus imparting compressive and retractive movement to the mold' plunger 10.

It willv be noted that the application of the predetermined steam pressure to the bottom of the. piston 18, will exert a= predetermined upward pressure on the outer end of the lever element 14. The amount of pressure imparted to the mold plunger 10 by the toggles 12-13, is not, however, of a fixed or a predetermined quantity, but will vary with the point at which resistance to upward compressive movement of the mold plunger 10 is encountered. This point is likely to vary because of variations' 1n the amount or in the consistency of the material in the mold. Thus if the ultimate compression of the material in the mold be reached after 19g inches of movement of the mold 11o jplunger than if the'` point of ultimate fio compression be reached after the mold plunger 10 had completed lli inches of compressive movement. This difference in pressure arises, of course, from the different resolutions of forces 12-13 at different larity. The before described pressure mechanism vconstitutes one formof variable pressure applying mechanism. Such mechanisms are usually actuated by positive mechanical means, such as a cam acting on a roller mounted on V,the toggle ,adjacentV the joint thereof. The `Vusual cam and roller construction is objectionable Vfor several reasons,-theV most important of which are (1) that the rotative power imparted to the cam is necessarily very great and is available to ,produce breakage inthe event of interferrenceV or stoppage of any of the cooperating elements of the .press and (2) that the friction in the bearing of the roller and between the cam and roller cause heating and excessivelwear. The bearings ofthe toggle itself can, however, be of sufhcient'size to prevent heating orV undue wear. rlhe sliding movement 'between Vthe various toggle elements is intermittent and of comparatively limited extent.` Y

Thus my invention enables me to avail myself ofthe simplicity and durability of the toggle whileV eliminating the Vusual defects of 'such mechanism. Inpractice I prefer to provide sulicient steam pressure Vto assure a fullstroke of the'piston 18. in its cylinder 15, thereby imparting a Xed amountV of travel to the mold plunger 10.V To compensate for `.variance 1n the amount of material in the mold and the point at which ultimate compression of the co-mpressed material yis reached, I preferably provide cooperating yielding pressure limiting means, which prevents breakage' of the parts and limits the pressure applied to the compres-sedlmaterial lindependently ofthe pressure fluid actuation of the/toggle;

In compressing asphaltie and other plastic materials.r the resistance to compression is relatively slight at the beginning of the compression,` but increases progressively as the material is compressed. It has been the practice in pressure fluid actuated presses to conserve the pressure fluid supply by applying `a plurality `of compressions increasing in potential pressure. This necessarily complicates the structure; By the use of the pressure lluid means in combination with pressure 'multiplying means providing an increasing potential multiplication as compression proceeds, I 'am enabled to more nearly approach at each portion of the compression .that potential pressure necessary provided by the toggle points4 of,` relative angu- Y Vvide asingle to eect compression. This results in a great saving of the pressure fluid and also in a more evenly applied compressive movement of the mold plunger. f

y I will now describe the molding instrumentalities and will show in what way I have provided in connection with the molding instrumentalities, a preferred construction of yielding pressure determining means, for overcoming the disadvantages attending the variable potential pressures, applied by the compressive instrumentalities. I preferably provide, as shown, two columns 30-30 bolted at their lower ends to the bed plate 17 and arranged one on each side of the lever arm 14.-. I also preferably provide two supports 31-31 bolted to the opposite side of the bed plate 17 and provided Vmold block 34:, which is carried by the pressure receiving bulk-head 35, which is fulcrumed on the axis or shaft 33 and is free to rock about'said axis, when a predetermined limitof pressure has been applied to the contents of the mold. The bulkhead 35` is preferably made in two parts, as is best shown in Fig. 3, and carries the mold block 34 and also a rectilinearly reciprocable .element 39, havingl the pressure block 36 Vand the neck or conduit 37 provided with a hopper 38. The reciprocating element 39, carrying the pressure block and themold filling neck 37, may be conveniently described.V as the sliding head 39.

The bulk-head 35 constitutes one form of yielding abutment. Presses having yielding abutmentsA have heretoforeV been designed with-a shiftable mold, which oscillates or rectilinearly reciprocates, relative to the pressure block'or molded cover. The shiftable mold and cover which must be oscil-Y lated or reciprocated with it are necessarily much heavier than the rectilinearly reciprocable sliding head of the type herein disclosed, thus constituting a Speed 'restrictive element. Another advantage Yof the disclosed construction is that the mold, sliding head and bulk-head necessarily all yield together when the maximum [pressure is reached, thus avoiding separation of the mold from its mold cover, which produces a lin or roughness on the upper corners of the compressed block.

To reciprocate the sliding head automatically to fill the mold, cover the mold, uncover the mold and carry away the completed block, I may and preferably do pr cycle timing shaft 40, which may be carried in brackets 41-t1 on the frames 31-31, and which is preferably provided with a main cam 42 and auxiliary cams 42h-42a, adapted to oscillate a sliding head lever 43, which is. fulcrumed at its lower enclin a bearing 44 and which is connected at its upper end to the sliding head by a connecting rod 45. The cams 42, 42, 42a arepreferably inverse so that the same distance is constantly maintained between thel oppositely effective cooperating cam rollers. To impart oscillatory movement to the sliding head lever 43 by the cams 42, 42, 42, I preferably provide a roller 46 carried by the lever 43, and rollers 47--47 carried by springs 485-48. The roller 46 bears against the main cam 42, while the rollers 47-47 bear against the auxiliary cams 42-42 The .springs 48--48 preferably exert tension to move the rollers 47-47 toward the roller 46. Thus the contact of all three rollers with the main cam 42 and on the auxiliary cams 42-42, is at all times insured, preventing lost motion and breakage, which usually attend the use of race cams or inverse oppositely effective cams. To increase or decrease the tension on the springs 48-48, I have mounted them on rocker arms 459-49, to which they are pivoted at 50-50, and I have provided set screws 51H51, adapted when screwed in to increase the tension on the springs 48, and when slackened off to decrease such tension.V To prevent the springs 48-48 from swinging bodily about the point at which the rocker arms 49-49 are pivoted to the lever 43,. thus permitting the rollers 47-47 to get out `of proper relation to the cooperating cams 42a-42, I have provided pivoted supports 52-52, adapted to hold the rollers 47-47, and springs 48-48 in their proper operative position, while permitting oscillation of the lever 43.

.The springs 48-4S constitute a preferred construction of means for yieldingly maintaining contact between the rollers and the inverse cams 42 and 42". This is believed to be broadly new, as applied to producingl relative reciproca-tion of the mold and mold cover of `a molding press. The main cam 42 comprises threeconcentric arcuate portions of different radii connected by suitably inclined portions. These three arcuate portions index the three positions of the sliding head, the arcuate portion having the longest radius being in contact with the roller 46, when the sliding head is in its extreme right hand position with the mold 11 uncovered; the intermediate arcuate portion of the cam 42 being in contact with the roller 46, when the sliding head is in its intermediate position, as shown in the drawing, in which position pressure is applied to the contents of the mold; and the arcuate portion of the cam 40 having the shortest radius,being in Contact with the roller 46, when the sliding head is in its extreme forward position `with the neck or conduit 47 in register with the mold 11. The cam 42 actuates the movement of the sliding head in the right hand direction, as shown in Fig. 1, including the movement from the filling position to compressing position, and the movement from the compressing position to the mold emptying position, in which the sliding head uncovers the top of the mold, while the contents thereof are ejected by a mechanism to be hereinafter described. The main cam 42 is inverse to the auxiliary cams 42a-42, Vthe distance between the points of contact of the roller 46, and the points of contact of the rollers 47 being constant. The cams 42-42a move the sliding head through its longest movement from the mold emptying position to the mold filling position, this being caused by the oscillation of the lever 43 from right to left.

To empty the mold when uncovered, independent movement can be given to the mold plunger 10 by ejecting mechanism, which may and preferably does include an ejecting lever 60 fulcrumed at 6l on the frames 31, and having a roller 62 contacting with an ejecting cam 63 0n the timing shaft 40. On the opposite end of the lever 60, I preferably provide a roller 64 contacting with a shoe 65, carried by mold plunger guiding levers (S6-66, which are fulcrumed at 67H67 to brackets 68-68, carried by the bulk-head 35. The mold plunger guiding levers 66-66 are fulcrumed at 69 to the mold plunger 10 and in co'peration with the ejecting lever 60 and feed regulating means, hereinafter described, prevent the mold plunger from ever dropping entirely out of the mold. Keyed to the shaft 61, which is also the fulcrum of the ejecting lever 60, I preferably provide a feed regulating lever 70, which4 is connected to a feed rod 71, having a feed nut supported by a feed regulating screw 73, which is rotatable in the feed regulating nut 74 by any suitable means typified by the feed regulating arms 75. A manual rotation of the feed regulating arms 75 produces either upward or downward movement of the feed regulating screw 7 3 relative to the fixed feed regulating nut 74 and thus raises or depresses the rod 71, which through the lever 70, shaft 61, lever 60 and guide lever 66, regulates the drop of the mold plunger or the receiving capacity of the mold fWhen in filling position.

The relative timing of the compressive instrumentalities and molding instrumentalyities, before described, is assured by mounting the valve controlling cam 80 on the timing shaft 40. The cam 8() through levers 81 and 82 fulcrumed at 83 and S4, actuates reciprocation of the valve control rod 85, thereby causing rocking motion of the valve rocker shaft 86, on which is mounted a lever 87 adapted to impart reciprocatory motion to a slide valve 88 in the steam chest 89 of the steam cylinder 15. When the valve controlling lever 85 is rocked to the left, the steam is admitted from the valve chest 89, through the admission port 91a, thereby moving the piston 18v upwardly. At the same time the slide valve 88 has connected the exhaust port 91 with the exhaust 92, thereby permitting the escape of the steam from the upper part of the cylinder,'as the piston 18 moves upwardly. In the event that: no material is contained in the mold and no substantial resistance is opposed to the mold plunger, the piston 18 may move with great velocity and tend to strike the cylinder head 21. Tc prevent this a steam cushion is formed in advance of the piston 18' `as soon as the latter has passed the ex-4 haust port 91. This cushion is formed be-u cause the exhaust port 91 Vwill have been covered by the piston 18, while the admission port 93 is covered by theslide valve 88.

Conversely, the movement of the valve controlling element. to the'right produces downward movement of the slideV valve88, thereby openingthefadmission port 93 to the steam chest, ywhileopening the exhaust port 90 to the 'exhaust 92 and covering'the port 91a, 4to provide afluid pressure buffer between the piston 18 and the bottom ofthe cylinder 15. p l 1. I preferablyv interpose. in the -return admission port 93 the valve 93a, whereby. the rate of admission of pressure` fluid to the toprof `the'pistonv 18 be varied,..thus

preventingthe admission of too great la volume `of. steam to the top of the piston 18 for the Vreturn stroke of said` piston which might cause damage to" the machine.

I preferably provide the toggle members 12 and 13 with projections 200-201, 202- 203, 204-205 soproportioned and placed relative toV each other that when the piston 18 is at the-bottomof its stroke, these projections butt together, thereby lifting'each bearing of thel toggle slightly from its corresponding se'at, thereby permitting efficient y distribution of the oil -to the toggle bearings.

Whilel the before described fluid pressure buffer -mechanism is'very eiiicient, I

preferably provide'a form of floating valve so that the movement of the slide valve 88 is-controlled, not onlyl by the rocking of the valve rocker shaft 86, but also indirectly by v vide an arm l100 on the cross head 22, t0

the pressure fluid Vactuated movement of the piston 18. To this end I preferably prowhich arm isconnected one end of a link 101, the other end of said linkv101 being connected to a floating valve lever 102, car-V rymgan eccentric 103, about which is pro-- Yvided an eccentric strap 104 connected to the slide valve stem 105. f The valve lever 87 is connected to the eccentric 103 and forms the fulcrum thereof.

The operationofthe valve actuating and the floating valve vmechanismis as'follows:y s

' When the lever 85is inovedftothe left, it rocks the levers 86 and 87, .which form abellcranl, thusV raising the slide vvalve 85. "As steam is admitted to force the :piston 18 upward, thefloating valve lever `102 israised at one endby the link 101', rockingthe lever about the connection at `87 as a fulcrum,

thereby providingdownward movement to scribed isy peculiarly advantageous because of its compact form andits simplicity. 1` f Y O ne.` of the l.difliculties incidental -tov lthe maintenance-` of ay press yof :this `character is caused bythe leakage*ofimaterial from the' mold lliabout the mold plunger 10, as the material falls directlyon tothe mechanical pressure mechanism underneath,V as` herein typifiedfby the toggles 12e-13.1.1 prevent this material whichl is :gritty in its "nature,

.Y from getting into the jointsv of theltoggle,I

by` providing the upper endV of the toggle element 12V with a shield 110, fastened vto the toggle bearlng cap 11, which -is carried bythe mold plunger-carrying toggle shaftV 112. The toggle cap 111, the moldplunger carrying shaft 112 and thefguard `or apron 11,0, are allfreciprocable. with .the mold' plunger 10 during both its'compressiv'e andV e]ecting :,movement; QDuring thefejecting movement ofthe mold plunger 10, the toggle portion 12 is held in proper relation to the mold plunger carrying shafty 112 by an elongated portion of the rguard 110 constitiltingk the guiding apron 1102i, which serves notonly as a protection for the upper-togle bearing, but also as a guide. The uckle bearing 113 of the toggle issimilarly protected by guards 1.14, 115, 116,

while the lower toggle bearing 11.7 is pro! tected by guards 118-119-120- The ends of the toggle bearings 112-113 and 117, are

protected by similar sheet metal plates,

which serve not only to prevent the entrance of dust but to retalnr the oil in these bearings.

I will now describe the typical operation of the whole press. Let us assume that the time shaft 40 is turned in such position that the neck 37 is registered with mold 11. At

ton .and

this point the mold plunger 10 is in its lowest position as determined by the adjusting movement of the feed regulating screw 73; thus the material actuated by gravity will slide down the neck 37 filling the mold 11. The sliding head is then moved to the right by operation of the main cam 42 until the pressure block 36 covers the mold, as shown in Fig. 1. The valve cam then moves the valve rod 85, rocking the bell-crank 8- 87, thereby imparting movement to the slide valve 88, thus admitting steam below the piston 18. As the piston 18 responds to the pressure fluid, the arm 100 and the link 101 will rock the floating valve lever 102 about its connection with the lever 87, thereby tending to regulate the speed and movement of the piston 18 if too little resistance is encountered. When the piston 18 closes the port 91, it will encounter the pressure fluid cushion caused by closure of the port 93. The before described piston travel will raise the toggle lever element 14, thereby straightening the toggle 12-13 and imparting pressure to the mold plunger 10.

In the event that there is more material in the mold than can be compressed by the movement imparted to the mold plunger 10, the whole structure including the mold block 34, the bulk heads 35 and the sliding head will be rocked about the axis of the shaft 33. To predetermine the pressure which the bulk heads 35 and associated parts shall withstand prior to yielding, I provide any suitable form of pressure determining means, herein shown as projections 130 attached to the bulk heads 35 at the outer end, to which projections I may `connect weights or a steam cylinder and piston, thereby affording as desired, either gravity actuated pressure determining means or pressure fluid actuated pressure determining means. The normal position of the bulk-heads 35 and associated parts are determined by projections 131 on the columns 30, on which the bulk-head 35 and associated parts rest, except during the periods when pressure is applied.

After a suitable period, during which the material in the mold is held under compression, further rotation of the timing shaft 40 causes the valve cam 80 te move the valve control rod to the right, thereby moving the slide valve 88 downwardly and admitting pressure fluid to the top of the piston 18, through the admission port 93, thereby imparting downward movement to the pisto the mold plunger 10. After the mold plunger 10 has dropped sufficiently to relieve thepressure of the material in the mold, the sliding head is again moved to the `right i-n such position that the top of the mold 11 is uncovered. This movement to the right is actuated by the main cam 42 acting on the roller 46 yof the reciprocating sliding head 43. The mold'now being uncovered, the ejecting cam 03 rocks the lever 60,A thereby elevatinfr the mold plunger 10V which is guided by the mold plunger guide lever 66, thereby ejeeting the completed block from the mold 11. During this ejecting movement the upper bearing 11 of the upper toggle 12 is lifted away from the main portion 0f the toggle 12 the toggle 12 being supported by the apron 110% As soon as the mold plunger 10 has been elevated to such position that it is flush with the upper face of the mold block 34, the sliding head is moved to its extreme left hand position by operation of the main cams 42u-42 on the rollers 47. During such movementthe compressed block is pushed to the left from the top of the plunger 10 and 'at the end of such movement the neck 37 again registers with the mold 11. The mold plunger 10 is now permitted to drop by the ejecting cam 63, and the column of material passing down the neck fills the mold 11, thereby completing one cycle of operation of the entire press.

Power may be imparted to the timing shaft l40 from any suitable source, preferably through gearing typified by a pulley .140, pinion 141 and timing shaft gear 142.

The pressure-receiving abutment may be held down in any suitable way, preferably by means adapted to exert a constant amount of pressure thereon. This means may take the form of a weight, and this weight may conveniently take the form of a pipe, a column of water or other liquid therein and, if desired, a tank carried thereby so that the amount of pressure available may be varied in accordance with the amount of water pumped into or out of the system. In Fig. G I have shown such a pipe, column and tank extending upwardly through several floors of a building, the pipe being slidably guided through the vfloors and roof. Fig. 7 shows a detail of the mechanism vshown in Fig. 6.

'While the drawings show and while I have described one specific embodiment of my invention, it will be understood that vchanges involving alteration, substitution, omission, reversal and re-arrangement of parts and even changes in Inode of opera` tion may be made without departing from the scope of my invention. My invention and what I desire by Letters Patent to procure is best described in the following claims:

1. A block molding press comprising, in combination., a mold in which the blocks are compressed, a mold plunger reciprocable in said mold, a toggle for imparting compressive movement to said mold plunger, lever ymeans rigidly connected to that member of the toggle farthest removed from said lmold plunger, pressure fluidmeansacting on said lever for straightening' said toggle to actuate compressive movementV thereof, and'pressure-determining means for limiting the pressure applied to theY blocks in said mold.

2. A molding press comprising, `in combination, a mold, a plunger vertically reciprocable therein, a vertically arranged toggle, a lever rigidly connected to the lower portion of said toggle, a cylinder having va vertically arranged axis for swinging said lever to straighten said toggle, eyecting means for .imparting mold-emptying movement to said mold plunger independent of said toggle,and a shaft arranged on the opposite side of said toggle from'said cylinder for timing the periods of operation of said toggle andvof said ejecting means. A

3. A molding press comprising, in combination, a yielding pressure-receiving abutment, a fulcrum for said abutment, and

Vmeans operatively connected to said abut` ment for exerting downward pressure to resist pressure-actuated yielding movement thereof, said means providing for an upward strain on said fulcrum.V Y Y 4. A molding press comprising, in combination, a yielding pressure-receiving abutL ment, a mold and a mold cover reciprocabl inand yieldingwith said pressure-receiving abutment. Y

l5. A molding press comprising in combination a mold plunger, a toggle for imarting compressive movement thereto, ever means rigidly connected to operate said toggle,a pressure fluid cylinder, its piston, a crosshead for said piston and a plurality of connecting rods for transmitting pressure fluid actuated movement of said cross-head to'said lever means to actuate compressive movement of said toggle.

6. A molding pressA comprising in combination a mold plunger; a pressure fluid actuator vfor imparting compressive movement to said vmold plunger; and a ylelding abutment opposed to said mold plunger.

7. A molding press comprising in combination a yieldingly actuated, normally fixed throw mold plunger; a mold; a reciprocable closure for said mold; and ayielding support for said mold and said mold closure.

` 8. A molding press comprisingin combination a normally fixed throw mold plunger;

a yielding abutment; a mold block'and av nation a mold plunger; a mold block; a

sliding head and an abutment, said abutment being pivotally mounted for yielding movement at a predetermined pressure and carrying saidmold vblock and said sliding head.

10. A molding/'press comprising in combination a mo-ld plunger; a mold contain-ing' element; a closure for the" mold; operating means for relatively 'shifting said mold Vcontaining Yelement and said closure;1.alnd an abutment mounted for yielding movement ata predetermined pressure and carrying said mold containing elementv and the shiftable element.

l11. A molding press comprising in combination a mold, a plunger, a timing shaft,

Y a pressure Huid cylinder for operating the plunger, its piston, a valve cam on saidtiming shaft for actuating said valve, an eccentric operatively interposed'between said cam and said valve, andvmeans connected to said piston for turning said eccentricfto modify v means and a pivoted guide for said mold plunger effective to maintain said mold plunger in substantial'y alinement with said mold during its compressive and ejecting movements.

bination a mold; its mold cover and operating means for producing relative movement of said mold and mold cover; lsaid operating means including inverse cams; rollers for said cams; spring means connecting said rollers, and means for increasing andv deicreasing the pressure of saidrolle'rs on rsaid cams by increasing or decreasing the pressure of said spring means. f

, 15. In a molding press having a mold' and mold cover; operating means for changing the relative position of said mold andmold cover; said operating means including a lever connected to the moving part; ra rotary camshaft and inverse cams Vmounted thereon; a plurality of rollers coperating` 14. A molding press comprising-in comf with said vcams and operatively connected to v Vsaid lever; one of said rollers Ybeingon the same side, of said cam shaft as said lever;

lthe other roller being on the opposite side of said cam shaft.

16. In a molding press having mold and mold cover; operating means for changing the relative position of'said mold 4and mold cover; said operatingv meansfincluding a lever connected to the moving part, a rotary camshaft and inverse cams mounted thereon; a plurality of rollers coperating with said cams and operatively'connected to said.

lever; one of said rollers being on the same side of said cam shaft as said lever; the other roller being on the opposite side oi said cam shaft; and a support for the latter roller.

17. A molding press comprising in combination a mold plunger; a toggle for imparting comlpressive' movement to said mpld plunger; oil retaining means at the joints of said toggle and heels adjacent the joints of said toggle adapted to cause separation of the elements of the toggle at the joints thereof when said toggle is in iieXed position to permit the thorough lubrication of the joints of said toggle.

18. A molding press comprising in combination a mold plunger; a pressure fluid cylinder; a piston in said cylinder, one side of said piston being effective on the admission of steam to effect compressive movement of said mold plunger, and the other side of said piston being effective on the admission of steam to effect return movement of said piston; valve means for controlling the admission and exhaust of pressure fluid from each end of said cylinder; a return pressure fluid admission passage for admitting pressure fluid to the return end of said cylinder; a throttling element in said return admission passage; and an exhaust passage independent of said return admission passage ji'or permitting unthrottled exhaust of pressure Huid from the return end of said cylinder.

19. A molding press comprising in combination a mold plunger; a yielding abutment opposing said mold plunger; a pivoted support for said yielding abutment; and gravity actuated means projecting beyond the molding portion of the press and providing with said pivoted support, a second-class lever opposing the yielding of said abutment.

20. In a molding press having a mold and mold cover, operating means for changing the relative position of said mold and mold cover; said operating means including a rotary cam shaft and inverse cam means mounted thereon; a plurality of rollers cooperating With said cam means, one on one side of said shaft and the other on the opposite side of said shaft, and resilient means pressing said rollers together and against said cam means.

In testimony whereof, I have signed my name to this specification.

GEORGE E. WHITNEY.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

